Generally, the industry of semiconductor manufacturing involves highly complex techniques for fabricating integrated circuits using semiconductor materials which are layered and patterned onto a substrate, such as silicon. Due to the large scale of circuit integration and the decreasing size of semiconductor devices, the fabricated devices have become increasingly sensitive to defects. That is, defects which cause faults in the device are becoming increasingly smaller. The device needs to be generally fault free prior to shipment to the end users or customers.
Optical inspection of patterned wafers at the deep UV (ultraviolet) wavelength has been the main inspection solution for leading-edge integrated circuit (IC) fabrication in critical defect inspection and process control. As the IC industry continues to push the wafer pattern design towards smaller design rule for higher device density and better performance, the challenges to find yield-limiting defects in the wafer inspection also increases dramatically. Among them, one of the greatest challenges lies in control of wafer noise nuisances.
Accordingly, there is a continued demand for improved semiconductor wafer inspector systems and techniques.